Voice recognition device for vehicle

ABSTRACT

A voice recognition device includes a learning unit that learns a relationship between contents of the voice and information on the vehicle by storing recognized contents of the voice and the vehicle information at the time the voice is recognized in association with each other in a storage unit; a processing unit that calculates a recognition accuracy of the uttered voice each time an utterance is made; and an estimation unit that reads the vehicle information under a condition where the value calculated by the processing unit is less than a threshold. In a case where the vehicle information that has been read is in the storage unit, the contents of the voice associated with the vehicle information are estimated as contents of the voice. In a case where the estimation unit estimates contents of the voice, the control unit controls the vehicle on the basis of the estimated contents.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a voice recognition device for a vehicle thatcontrols the operation of the vehicle on the basis of contents of thevoice input by utterance.

2. Description of Related Art

A voice recognition device for a vehicle that controls the operation ofthe vehicle by recognizing the voice uttered by a vehicle occupant andtransmitting a command which is set in association with the recognitionresult to a device installed on the vehicle has been suggested.

An example of such voice recognition device for a vehicle is availablein which, for example, as described in Japanese Patent ApplicationPublication No. 2008-26464 (JP2008-26464 A), the state of the road onwhich the vehicle travels is estimated according to the vehicle speed,and a command of interest is restricted according to the estimationresult, thereby improving the voice recognition rate when controllingthe vehicle operation.

However, with the device described hereinabove, when the vehicle is at alocation where a sudden sound is generated, for example, at a railroadcrossing, the voice input to the device can include a large noise and asufficient voice recognition accuracy cannot be obtained. Thus, wherethe voice is difficult to recognize even when the command of interest isrestricted according to the state of the road, the accuracy of vehicleoperation control based on voice recognition decreases.

SUMMARY OF THE INVENTION

The invention provides a voice recognition device for a vehicle thatmakes it possible to increase further the accuracy of vehicle operationcontrol based on voice recognition.

A first aspect of the invention relates to a voice recognition devicefor a vehicle that is installed on the vehicle and equipped with acontrol unit that controls the vehicle on the basis of contents of thevoice recognized from an utterance. The voice recognition deviceincludes a learning unit that learns a relationship between the contentsof the voice and information on the vehicle by storing the contents ofthe voice in a vehicle information storage unit in association with thevehicle information at the time the voice is recognized; a recognitionaccuracy calculation unit that calculates a recognition accuracy of thevoice each time the voice recognition is performed; and an utteranceestimation unit that reads the vehicle information in a case where therecognition accuracy is lower than a predetermined threshold andestimates that the contents of the voice associated with the vehicleinformation are contents of an uttered voice when the vehicleinformation that has been read is in the vehicle information storageunit, wherein, in a case where the contents of the voice are estimatedby the utterance estimation unit, the control unit controls the vehicleon the basis of the estimated contents of the voice.

According to the abovementioned aspect, even when a sufficient voicerecognition accuracy is not ensured because the uttered voice includes alarge noise or the like, the vehicle information at the time the voiceis recognized is learned in association with the recognized contents ofthe voice. As a result, the utterance contents are estimated accordingto the mode in which the driver operates the vehicle. Therefore, thecontrol region such that becomes the so-called dead zone can beeliminated and the accuracy of vehicle operation control based on voicerecognition can be further increased.

In the voice recognition device for a vehicle according to first aspectof the invention, under a condition where the recognition accuracycalculated by the recognition accuracy calculation unit is equal to orgreater than the predetermined threshold, the learning unit may storethe recognized contents of the voice and the vehicle information at thistime in association with each other in the vehicle information storageunit

According to the abovementioned aspect, the vehicle information at thetime the voice is recognized with good accuracy can be learned inassociation with the recognized contents of the voice. As a result, theutterance contents are estimated more accurately according to the modein which the driver operates the vehicle. Therefore, the accuracy ofvehicle operation control based on voice recognition can be furtherincreased.

In the voice recognition device for a vehicle according to first aspectof the invention, under a condition where the recognition accuracycalculated by the recognition accuracy calculation unit is equal to orgreater than the predetermined threshold, the learning unit may storethe recognized contents of the voice and the vehicle information over aconstant period of time before and after the condition is satisfied inassociation with each other in the vehicle information storage unit.

According to the abovementioned aspect, the vehicle information over aconstant period of time before and after the voice is recognized withgood accuracy is learned in association with the recognized voicecontents. As a result, the utterance contents are estimated moreaccurately according to the series of modes in which the driver operatesthe vehicle over a constant period of time. Therefore, the accuracy ofvehicle operation control based on voice recognition can be furtherincreased.

In the voice recognition device for a vehicle according above aspect ofthe invention, the learning unit may prohibit the storage of the vehicleinformation in the vehicle information storage unit, under a conditionwhere the recognition accuracy calculated by the recognition accuracycalculation unit is less than the predetermined threshold.

In the voice recognition device for a vehicle according to first aspectof the invention, the voice recognition device for a vehicle may furtherincludes an utterance subject identification unit that identifies anutterance subject of the voice, wherein the learning unit may store thevehicle information in the vehicle information storage unit for eachutterance subject identified by the utterance subject identificationunit; and the utterance estimation unit may retrieve the utterancesubject identified by the utterance subject identification unit from thevehicle information storage unit and may estimate the contents of thevoice corresponding to the utterance subject, in a case where theuttered voice contents are estimated on the basis of the vehicleinformation.

According to the abovementioned aspect, the vehicle operation iscontrolled according to each operation mode of the vehicle by differentdrivers using the same vehicle. Therefore, general versatility of thevehicle operation control based on voice recognition can be increased.

A second aspect of the invention relates to a voice recognition devicefor a vehicle. The voice recognition device includes: a vehicleinformation storage unit that stores the contents of voice and vehicleinformation in association with each other; a recognition accuracycalculation unit that calculates a recognition accuracy of the utteredvoice each time the voice recognition is performed; and an utteranceestimation unit that reads the vehicle information when the recognitionaccuracy is lower than a predetermined threshold and estimates that thevoice contents associated with the vehicle information are contents ofan uttered voice when the vehicle information that has been read is inthe vehicle information storage unit, wherein, when voice contents areestimated by the utterance estimation unit, the control unit controlsthe vehicle on the basis of the estimated voice contents.

According to the abovementioned aspect, even when a sufficient voicerecognition accuracy is not ensured because the uttered voice includes alarge noise or the like, the vehicle information at the time the voiceis recognized is learned in association with the recognized contents ofthe voice. As a result, the utterance contents are estimated on thebasis of the vehicle information stored in association with the vehicleinformation at this time. Therefore, the control region such thatbecomes the so-called dead zone can be eliminated and the accuracy ofvehicle operation control based on voice recognition can be furtherincreased.

In the voice recognition device for a vehicle according to second aspectof the invention, the voice recognition device for a vehicle may furtherincludes an utterance subject identification unit that identifies anutterance subject of the voice, wherein the vehicle information storageunit may store the vehicle information for each utterance subject inassociation with the contents of the voice thereof, and the utteranceestimation unit may retrieve the utterance subject identified by theutterance subject identification unit from the vehicle informationstorage unit and may estimate the contents of the voice corresponding tothe utterance subject, in a case where the uttered voice contents areestimated on the basis of the vehicle information.

According to the abovementioned aspect, the vehicle operation iscontrolled under the control conditions that individually correspond todifferent drivers using the same vehicle. Therefore, general versatilityof the vehicle operation control based on voice recognition can beincreased.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the invention will be described below withreference to the accompanying drawings, in which like numerals denotelike elements, and wherein:

FIG. 1 is a block diagram illustrating the schematic configuration of avehicle using the voice recognition device for a vehicle of the firstembodiment;

FIG. 2 is a schematic diagram illustrating an example of vehicleinformation stored in association with the utterance contents in thevehicle information storage unit of the first embodiment;

FIG. 3 is a flowchart illustrating the procedure of voice recognitionprocessing executed by the voice recognition unit of the firstembodiment;

FIG. 4 is a schematic diagram illustrating an example of vehicleinformation stored in association with the utterance contents in thevehicle information storage unit in the voice recognition device for avehicle of the second embodiment; and

FIG. 5 is a schematic diagram illustrating the positional relationshipof vehicle travel positions that are stored as vehicle information bythe vehicle information storage unit of the second embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS First Embodiment

The first embodiment of the voice recognition device for a vehicle willbe described hereinbelow with reference to the appended drawings. Asdepicted in FIG. 1, the vehicle using the voice recognition device for avehicle of the present embodiment is provided with a vehicle speedsensor 101, a global positioning system (GPS) 102, a communicationdevice 103, and a window opening-closing sensor 104, and thosecomponents are electrically connected to an onboard controller 120.

The vehicle speed sensor 101 detects the vehicle speed and outputs asignal corresponding to the detected vehicle speed to the onboardcontroller 120. The GPS 102 receives a GPS satellite signal fordetecting the absolute position of the vehicle carrying the GPS 102.Further, the GPS 102 specifies the travel position of the vehicle on thebasis of the received GPS satellite signal and outputslatitude-longitude information indicating the specified travel positionto the onboard controller 120. The communication device 103, forexample, acquires environmental information (external air temperature,weather, traffic congestion state, and the Eke) on the vehiclesurroundings by wireless communication with a control center. Thecommunication device 103 outputs the acquired environmental informationto the onboard controller 120. The window opening-closing sensor 104detects the opening-closing state of the vehicle window and outputs asignal corresponding to the detected opening-closing state to theonboard controller 120.

The onboard controller 120 of the present embodiment also includes avoice recognition unit 130 that recognizes a voice of the vehicleoccupant. The voice recognition unit 130 has a recognition processingunit 131 that inputs the voice signal produced by the vehicle occupantthrough a microphone 140 provided at the vehicle.

The recognition processing unit 131, for example, divides the voiceinput from the microphone 140 into a plurality of sections having apredetermined time slot and matches, by dynamic programming (DP)matching, or the like, the characteristic vector of the voice containedin the divided sections with a characteristic vector of the voicepattern that has been prepared in advance. The recognition processingunit 131 also recognizes the voice pattern with the highest degree ofsimilarity of the characteristic vector as the contents of the voiceproduced in the section and converts the recognized contents of thevoice into text data. The recognition processing unit 131 also inputsthe converted text data into a learning unit 132.

The recognition processing unit 131 also functions as a recognitionaccuracy calculation unit that calculates the recognition rate(recognition accuracy) of voice recognition in an utterance each timethe utterance is made or each time voice recognition is performed. Thiscalculation of the recognition rate is performed, for example, on thebasis of a value obtained by adding up the degrees of similarity of thecharacteristic vector of the voice contained in one utterance and thecharacteristic vector of the voice converted into the text data for allof the sections including the utterance. The recognition processing unit131 also inputs the calculated recognition rate of voice recognitioninto the recognition rate determination unit 133.

The recognition rate determination unit 133 determines whether or notthe value of the recognition rate input from the recognition processingunit 131 is equal to or greater than a predetermined threshold X thathas been set in advance. In this case, the predetermined threshold X isset as a reference value for determining as to whether or not thevehicle operation is adequately controlled on the basis of the contentsof the voice recognized by the recognition processing unit 131. Further,when it is determined that the value of the recognition rate input fromthe recognition processing unit 131 is equal to or greater than thepredetermined threshold X, the recognition rate determination unit 133outputs a signal indicating the positive determination to the learningunit 132. Meanwhile, where it is determined that the value of therecognition rate input from the recognition processing unit 131 is lessthan the predetermined threshold X, the recognition rate determinationunit 133 inputs a signal indicating the negative determination to thelearning unit 132.

The voice recognition unit 130 of the present embodiment also has anindividual identification unit 134 electrically connected to a wirelesscommunication unit 141 provided at the vehicle. The wirelesscommunication unit 141 inputs into the individual identification unit134 information on the individual ID included in the informationtransmitted by wireless communication from a portable informationterminal 200 owned by the vehicle occupant.

The individual identification unit 134 functions as an utterance subjectidentification unit that identifies a vehicle occupant as an utterancesubject on the basis of information on the individual ID input from thewireless communication unit 141. Where a plurality of occupants ispresent in the vehicle and information on a plurality of individual IDis input through the wireless communication unit 141 from the portableinformation terminals 200 owned by the occupants, the individualidentification unit 134 may output a list of the owners of the portableinformation terminals 200 identified by the individual ID to a monitorinstalled on the vehicle and display the list. In this case, the drivermay set himself/herself as the utterance subject by selectinghimself/herself from the list of owners displayed at the monitor.

Where the learning unit 132 inputs the signal indicating the positivedetermination from the recognition rate determination unit 133, thelearning unit matches the text data input from the recognitionprocessing unit 131 with a model of utterance contents. The learningunit 132 then identifies the matched utterance contents from the modelas the contents of the utterance made by the vehicle occupant. In thiscase, the model is generated by applying a modeling method such asBayesian networks or a decision tree to the text data of the utterancecontents that have been prepared in advance.

The learning unit 132 also stores the identified utterance contents inthe vehicle information storage unit 135 in association with the vehicleinformation at the time the voice is recognized, for each vehicle driveridentified by the individual identification unit 134. In this case, thevehicle information includes the travel position of the vehicle, dateand time, vehicle speed, weather around the vehicle, opening-closingstate of the vehicle windows, and the like. In the example illustratedby FIG. 2, a first utterance V1 (“OPEN A WINDOW”) and a second utteranceV2 (“REDUCE AUDIO SOUND LEVEL”) are stored in the vehicle informationstorage unit 135 in association with the vehicle information at threepoints in time at which those utterances have been made. In thisexample, the driver “A” who is the utterance subject is the same, thetravel position “P1” of the vehicle is also the same, and moreover, thewindows of the vehicle are “CLOSED” at each point of time at which theutterances V1 and V2 have been identified. Meanwhile, when the firstutterance V1 is identified, the weather around the vehicle is “CLEAR” ateach point of time, whereas when the second utterance V2 is identified,the weather around the vehicle is “RAIN” at each point of time. Thus, inthis example, when the vehicle is operated by the driver “A” so that thevehicle travels at a specific travel position “P1” in a state withclosed windows, the contents of the utterance made by the driver “A”tends to be consistent with the weather around the vehicle at this time.

Where the recognition rate determination unit 133 determines that thevalue of the recognition rate input from the recognition processing unit131 is equal to or greater than the predetermined threshold X, berecognition rate determination unit outputs a signal indicating thepositive determination to the control unit 136. When the signalindicating the positive determination is input from the recognition ratedetermination unit 133, the control unit 136 reads from the learningunit 132 the information indicating the utterance contents identified bymatching the model of utterance contents with the text data input by thelearning unit 132 from, the recognition processing unit 131. The controlunit 136 then controls the operation of an actuator 150 under thecontrol conditions corresponding to the utterance contents read from thelearning unit 132. In the present embodiment, the actuator 150 controlsthe operation of various onboard devices, such as the opening-closingoperation of the vehicle windows, operation of audio devices installedon the vehicle, and ON/OFF operation of the turn signal of the vehicle.

Meanwhile, when the signal indicating the negative determination isinput from the recognition rate determination unit 133, the learningunit 132 does not matches the model of utterance contents with the textdata input from the recognition processing unit 131. Thus, when thesignal indicating the negative determination is input from therecognition rate determination unit 133, the learning unit 132 prohibitsthe storage of the vehicle information at this time in the vehicleinformation storage unit 135 in association with the contents of thevoice input from the microphone 140.

When the value of the recognition rate input from the recognitionprocessing unit 131 is determined to be less than the predeterminedthreshold X, the recognition rate determination unit 133 also outputsthe signal indicating the negative determined to the utteranceestimation unit 137. When the signal indicating the negativedetermination is input from the recognition rate determination unit 133,the utterance estimation unit 137 acquires the vehicle information atthis time into the learning unit 132 on the basis of the signals inputfrom the vehicle speed sensor 101, GPS 102, communication device 103,and window opening-closing sensor 104 into the learning unit 132, andreads the acquired vehicle information from the learning unit 132. Theutterance estimation unit 137 also reads the information stored in thevehicle information storage unit 135 from the learning unit 132. Then,the utterance estimation unit 137 retrieves the utterance subjectidentified by the individual identification unit 134 from among theinformation which has been read from the vehicle information storageunit 135, and extracts the information with the highest degree ofsimilarity to the vehicle information, which has been read from thelearning unit 132, from among the information obtained by the retrieval.The utterance estimation unit 137 then estimates the utterance contents,which corresponds to the extracted information, as the contents of theutterance made by the vehicle occupant. Then, the utterance estimationunit 137 outputs a signal indicating the estimated utterance contents tothe control unit 136. The control unit 136 controls the operation of theactuator 150 under the control conditions corresponding to theestimation result on the utterance contents input from the utteranceestimation unit 137.

The schematic procedure of the voice recognition processing executed bythe voice recognition unit 130 in the voice recognition device for avehicle of the present embodiment will be explained hereinbelow withreference to the flowchart in FIG. 3. The voice recognition unit 130executes the voice recognition processing depicted in the FIG. 3 eachtime a voice is input through the microphone 140. The recognitionprocessing unit 131 recognizes the contents of the voice input throughthe microphone 140 (step S10).

Then, the individual identification unit 134 identifies the occupants ofthe vehicle on the basis of the information on the individual ID inputfrom the wireless communication unit 141, and sets the voice utterancesubject from among the identified occupants (step S11).

Then the recognition rate determination unit 133 reads from therecognition processing unit 131 the recognition rate of voicerecognition, which has been calculated during the contents of the voicerecognition performed by the recognition processing unit 131 in thepreceding step S10, and determines whether or not the recognition ratewhich has been read is equal to or greater than the predeterminedthreshold X (step S12).

Where the recognition rate, which has been read by the recognition ratedetermination unit 133, is equal to or greater than the predeterminedthreshold X (step S12=YES), the learning unit 132 identifies thecontents of the utterance made by the vehicle occupant by matching thecontents of the voice recognized by the recognition processing unit 131in the preceding step S10 with the model of utterance contents. Thelearning unit 132 also stores the identified utterance contents inassociation with the vehicle information at the time the voice isrecognized in the vehicle information storage unit 135, for eachutterance subject identified by the individual identification unit 134in the preceding step S11 (step S13). The control unit 136 controls theoperation of the actuator 150 under the control conditions correspondingto the utterance contents identified in the preceding step S13 (stepS14).

Meanwhile, when the recognition rate which has been read from therecognition rate determination unit 133 is determined in the precedingstep S12 to be less than the predetermined threshold X (step S12=NO),the utterance estimation unit 137 acquires the vehicle information atthis time into the learning unit 132 and reads the acquired vehicleinformation from the learning unit 132 (step S15). The utteranceestimation unit 137 then estimates the contents of the utterance made bythe vehicle occupant on the basis of the vehicle information read fromthe learning unit 132 (step S16). The control unit 136 then controls theoperation of the actuator 150 under the control conditions correspondingto the utterance contents estimated in the preceding step S16 (stepS17).

For example, the vehicle travel position “P1”, the opening-closing state“CLOSED” of the vehicle window, and the weather “CLEAR” around thevehicle are taken as the vehicle information at the time the voice isrecognized. In this case, in the example illustrated by FIG. 2, theutterance contents of “OPEN A WINDOW” are stored in association withthis vehicle information in the vehicle information storage unit 135.Therefore, where the recognition rate which has been read by therecognition rate determination unit 133 is less than the predeterminedthreshold X under such conditions, the utterance estimation unit 137estimates the utterance contents of “OPEN A WINDOW” as the contents ofthe utterance made by the vehicle occupant. The control unit 136 thencontrols the actuator 150 to perform the operation of opening thevehicle window in response to the utterance contents of “OPEN A WINDOW”,which are the utterance contents estimated by the utterance estimationunit 137.

In another case, the vehicle travel position is “P1” and the windowopening-closing state of the vehicle is “CLOSED”, as in theabove-described case, but the weather around the vehicle is “RAIN”,which is different from the above-described case, in the vehicleinformation at the time the voice is recognized. In this case, in theexample depicted in FIG. 2, the utterance contents, of “REDUCE AUDIOSOUND LEVEL” is stored in association with such vehicle information inthe vehicle information storage unit 135. Therefore, when therecognition rate, which has been read by the recognition ratedetermination unit 133, is less than the predetermined threshold X undersuch conditions, the utterance estimation unit 137 estimates theutterance contents of “REDUCE AUDIO SOUND LEVEL” as the contents of theutterance made by the vehicle occupant. The control unit 136 thenperforms the operation of reducing the audio sound level by controllingthe actuator 150 in response to the utterance contents of “REDUCE AUDIOSOUND LEVEL”, which are the utterance contents estimated by theutterance estimation unit 137.

The operation of the voice recognition device, in particular, the voicerecognition unit 130, of the present embodiment is explained below. Inthe present embodiment, when the recognition rate of the voice inputthrough the microphone 140 is equal to or greater than the predeterminedthreshold X, the utterance contents are identified on the basis of therecognized contents of the voice. In this case, not only the operationof the actuator 150 is controlled under the control conditionscorresponding to the identified utterance contents, but the identifiedutterance contents are also stored in association with the vehicleinformation at this time in the vehicle information storage unit 135.

Furthermore, where the recognition rate of the voice input through themicrophone 140 is less than the predetermined threshold X, theinformation with the highest degree of similarity to the vehicleinformation at this time is retrieved from among the information storedin the vehicle information storage unit 135. The utterance contentscorresponding to the retrieved information is estimated as the contentsof the utterance made by the vehicle occupant, and the operation of theactuator 150 is controlled under the control conditions corresponding tothe estimation result.

In this case, when the utterance contents are estimated, the contents ofthe voice input through the microphone 140 is not taken into account.Therefore, even when the recognition rate of the voice input through themicrophone 140 has greatly decreased, where the information with a highsimilarity to the vehicle information at this time is stored in thevehicle information storage unit 135, the contents of the utterance madeby the vehicle occupant can be estimated. Thus, where the voice inputthrough the microphone 140 has been accurately recognized at least oncein the past under the conditions same as or similar to the vehicleinformation at the time the present utterance is made, even when therecognition rate of the voice at the time the present utterance is madehas decreased, the utterance contents can be accurately estimated.

In particular, in the present embodiment, after the utterance subjecthas been identified, the utterance contents are stored in associationwith the vehicle information at this time in the vehicle informationstorage unit 135 for each identified utterance subject. Therefore, evenwhen the same vehicle is operated by different drivers, the operation ofthe actuator 150 can be controlled under the control conditions suitablefor the vehicle operation mode of each driver.

Further, in the present embodiment, the utterance subject is identifiedon the basis of the information on the individual ID input by wirelesscommunication from the portable information terminal 200 owned by thevehicle occupant. Therefore, when the utterance subject is identified,the contents of the voice input through the microphone 140 is not takeninto account. Therefore, even when the recognition rate of the voiceinput through the microphone 140 has greatly decreased, the utterancesubject can be identified.

As described hereinabove, the following effects can be obtained inaccordance with the first embodiment. (1) Even when a sufficient voicerecognition accuracy is not ensured because the uttered voice includes alarge noise, the utterance contents are estimated on the basis of thecontents of the voice stored in association with the vehicle informationat the time the voice is recognized in the vehicle information storageunit 135. Therefore, the control region such that becomes the so-calleddead zone can be eliminated and the accuracy of vehicle operationcontrol based on voice recognition can be further increased.

(2) The vehicle information at the time the voice is recognized isstored in association with the recognized contents of the voice in thevehicle information storage unit 135. As a result, the utterancecontents are estimated more accurately according to the mode in whichthe driver operates the vehicle. Therefore, the accuracy of vehicleoperation control based on voice recognition can be further increased.

(3) The vehicle information at the time the voice recognition accuracyis equal to or greater than the predetermined threshold X and the voiceis recognized with good accuracy is stored in association with therecognized contents of the voice in the vehicle information storage unit135. As a result, the utterance contents are estimated more accuratelyaccording to the mode in which the driver operates the vehicle.Therefore, the accuracy of vehicle operation control based on voicerecognition can be further increased.

(4) Where the voice recognition accuracy is less than the predeterminedthreshold X and the voice is not recognized with good accuracy, thevehicle information is not stored in the vehicle information storageunit 135. Therefore, the accuracy of vehicle operation control in thecase in which a sufficient voice recognition accuracy is not ensured ismaintained at a suitable level.

(5) The utterance estimation unit 137 retrieves the identified utterancesubject from the information stored in the vehicle information storageunit 135 and estimates the uttered contents of the voice from among thecontents of the voice corresponding to the retrieved utterance subject.As a result, the vehicle operation is controlled according to each modeof vehicle operation by different drivers using the same vehicle.Therefore, general versatility of the vehicle operation control based onvoice recognition can be increased.

Second Embodiment

The second embodiment of the voice recognition device for a vehicle willbe described hereinbelow with reference to the appended drawings. In thesecond embodiment, the contents of vehicle information that are storedby the learning unit 132 in the vehicle information storage unit 135 aredifferent from those of the first embodiment. Therefore, in theexplanation below, the attention is focused on the features differentfrom those of the first embodiment, and the redundant explanation of thefeatures that are same as or correspond to those of the first embodimentis omitted.

The learning unit 132 of the present embodiment stores the utterancecontents identified by matching the text data input from the recognitionprocessing unit 131 with the model of utterance contents in the vehicleinformation storage unit 135 in association with the vehicle informationover a constant period of time before and after the voice is recognized.In this case, the date and time included in the vehicle information havea constant time slot.

In the example depicted in FIG. 4, the learning unit 132 stores theutterance contents in the vehicle information storage unit 135 inassociation with the vehicle information for a period of 5 secondsbefore and after the utterance contents has been identified, and thedate and time included in the vehicle information have a time slot of 5seconds. In this example, the third utterance V3 (“SWITCH ON A TURNSIGNAL”) and the fourth utterance V4 (“OPEN A WINDOW”) are stored in thevehicle information storage unit 135 in association with the vehicleinformation at three dates/times at which those utterances have beenmade. The driver “A” who is the subject of the utterances is the sameand the weather around the vehicle is “CLEAR” at each date/time at whichthe utterances V3 and V4 have been identified. Furthermore, the windowsof the vehicle are “CLOSED” at each date/time. Meanwhile, when the thirdutterance V3 has been identified, the vehicle travel position is “MOVEDFROM P2 TO P3”, whereas when the fourth utterance V4 has beenidentified, the vehicle travel position is “MOVED FROM P2 TO P4”. Inthis case, as depicted in FIG. 5, the “MOVEMENT FROM P2 TO P3”corresponds to the vehicle turning left at the intersection, whereas the“MOVEMENT FROM P2 TO P4” corresponds to the vehicle advancing straightthrough the intersection. Thus, in this example; when the vehicle isoperated by the driver “A” to travel through a specific intersectionwhen the weather is “CLEAR” in a state with closed windows, the contentsof the utterance made by the driver “A” tends to be consistent with thevehicle travel mode at this intersection.

Accordingly, for example, the vehicle travel position “MOVED FROM P2 TOP3”, the weather “CLEAR” around the vehicle, and the vehicle windowopening-closings state “CLOSED” are taken as the vehicle information atthe time the voice is recognized. In this case, in the example depictedin FIG. 4, the utterance contents of “SWITCH ON A TURN SIGNAL” is storedin association with this vehicle information in the vehicle informationstorage unit 135. Therefore, when the recognition rate which has beenread by the recognition rate determination unit 133 is less than thepredetermined threshold X under such conditions, the utteranceestimation unit 137 estimates the utterance contents of “SWITCH ON ATURN SIGNAL” as the contents of the utterance made by the vehicleoccupant. The control unit 136 then performs the operation of switchingon the left-turn signal by operating the actuator 150 in response to theutterance contents of “SWITCH ON A TURN SIGNAL” which are the utterancecontents estimated by the utterance estimation unit 137.

In another case, the weather around the vehicle is “CLEAR” and thevehicle window closing-opening state is “CLOSED”, as in theabove-described case, but the vehicle travel position is “MOVED FROM P2TO P4”, which is different from the above-described case, in the vehicleinformation at the time the voice is recognized. In this case, in theexample depicted in FIG. 4, the utterance contents of “OPEN A WINDOW” isstored in association with such vehicle information in the vehicleinformation storage unit 135. Therefore, when the recognition rate,which has been read by the recognition rate determination unit 133, isless than the predetermined threshold X under such conditions, theutterance estimation unit 137 estimates the utterance contents of “OPENA WINDOW” as the contents of the utterance made by the vehicle occupant.The control unit 136 then performs the operation of opening the vehiclewindow by controlling the actuator 150 in response to the utterancecontents of “OPEN A WINDOW”, which are the utterance contents estimatedby the utterance estimation unit 137.

Therefore, according to the second embodiment, the following effects canbe obtained in addition to the effects (1) to (5) of the firstembodiment. (6) The vehicle information over a constant period of timebefore and after the time at which the voice has been accuratelyrecognized is stored in association with the recognized contents of thevoice in the vehicle information storage unit 135. As a result, theutterance contents are estimated more accurately according to the seriesof modes in which the driver operates the vehicle over a constant periodof time. Therefore, the accuracy of vehicle operation control based onvoice recognition can be further increased.

The above-described embodiments can be also implemented in the followingforms. —In the embodiments, a method for identifying the utterancesubject is not limited to that based on the information on theindividual ID which is transmitted by wireless communication from theportable information terminal 200. For example, the utterance subjectmay be identified by recognizing the voiceprint of the voice inputthrough the microphone 140.

In the embodiments, the learning unit 132 may store the vehicleinformation at the time the voice is recognized in the vehicleinformation storage unit 135 without discriminating the vehicleinformation between the utterance subjects. In this case, the voicerecognition unit 130 may be not provided with the individualidentification unit 134 for identifying the utterance subject of thevoice.

In the embodiments, the learning unit 132 may store the recognizedcontents of the voice in association with the vehicle information at thetime the voice is recognized in the vehicle information storage unit 135even when the recognition rate which has been read by the recognitionrate determination unit 133 is less than the predetermined threshold X.

In the embodiments, where the predetermined threshold X, which serves asa criterion for determining whether or not the control of vehicleoperation is adequate on the basis of the contents of the voicerecognized by the recognition processing unit 131, is taken as a firstthreshold, a value less than the first threshold may be set as a secondthreshold. In this case, where the value of the recognition rate inputfrom the recognition processing unit 131 is equal to or greater than thesecond threshold and less than the first threshold, the utteranceestimation unit 137 may estimate the utterance contents on the basis ofthe vehicle information at this time while taking into account thecontents of the voice input through the microphone 140. Meanwhile, wherethe value of the recognition rate input from the recognition processingunit 131 is less than the second threshold, the utterance estimationunit 137 may estimate the utterance contents on the basis of the vehicleinformation at this time, without taking into account the contents ofthe voice input through the microphone 140.

In the embodiments, the recognition processing unit 131 may input theinformation on the voice waveform into the learning unit 132, withoutconverting the recognized contents of the voice into text data. In thiscase, the learning unit 132 matches the information on the voicewaveform input from the recognition processing unit 131 with theutterance contents model and identifies the matched utterance contentsfrom the model as the contents of the utterance made by the vehicleoccupant. In this case, the model includes the information on the voicewaveform corresponding to the utterance contents that has been preparedin advance.

In the embodiments, the contents of the voice and vehicle informationmay be stored in advance in association with each other in the vehicleinformation storage unit 135 when the initial settings are made for thevehicle. In this case, when the voice input through the microphone 140is recognized, the recognized contents of the voice may be associatedwith the vehicle information at this time and additionally stored in thevehicle information storage unit 135. Further, when the voice inputthrough the microphone 140 is recognized, the recognized contents of thevoice may be not stored in association with the vehicle information atthis time in the vehicle information storage unit 135. In this case, thevoice recognition unit 130 may be not provided with the learning unit132. Further, in this case, the vehicle information storage unit 135 maystore the vehicle information for each utterance subject, or may storethe vehicle information without discriminating the vehicle informationbetween the utterance subjects.

1. A voice recognition device for a vehicle which is installed on thevehicle and equipped with a control unit that controls the vehicle onthe basis of contents of a voice recognized from an utterance, the voicerecognition device comprising: a learning unit that learns arelationship between the contents of a voice and information on thevehicle by storing the contents of the voice in a vehicle informationstorage unit in association with the vehicle information at the time thevoice is recognized; a recognition accuracy calculation unit thatcalculates a recognition accuracy of the voice each time the voicerecognition is performed; and an utterance estimation unit that readsthe vehicle information in a case where the recognition accuracy islower than a predetermined threshold and estimates that the contents ofthe voice associated with the vehicle information are contents of anuttered voice when the vehicle information that has been read is in thevehicle information storage unit, wherein the control unit controls thevehicle on the basis of the contents of the voice in a case where thecontents of the voice are estimated by the utterance estimation unit. 2.The voice recognition device for a vehicle according to claim 1,wherein, under a condition where the recognition accuracy calculated bythe recognition accuracy calculation unit is equal to or greater thanthe predetermined threshold, the learning unit stores the recognizedcontents of the voice and the vehicle information at this time inassociation with each other in the vehicle information storage unit. 3.The voice recognition device for a vehicle according to claim 1,wherein, under a condition where the recognition accuracy calculated bythe recognition accuracy calculation unit is equal to or greater thanthe predetermined threshold, the learning unit stores the recognizedcontents of the voice and the vehicle information over a constant periodof time before and after the condition is satisfied in association witheach other in the vehicle information storage unit.
 4. The voicerecognition device for a vehicle according to claim 1, wherein thelearning unit prohibits the storage of the vehicle information in thevehicle information storage unit, under a condition where therecognition accuracy calculated by the recognition accuracy calculationunit is less than the predetermined threshold.
 5. The voice recognitiondevice for a vehicle according to claim 1, further comprising: anutterance subject identification unit that identifies an utterancesubject of the voice, wherein the learning unit stores the vehicleinformation in the vehicle information storage unit for each utterancesubject identified by the utterance subject identification unit; and theutterance estimation unit retrieves the utterance subject identified bythe utterance subject identification unit from the vehicle informationstorage unit and estimates the contents of the voice corresponding tothe utterance subject, in a case where the uttered contents of the voiceare estimated on the basis of the vehicle information.
 6. A voicerecognition device for a vehicle which is installed on the vehicle andequipped with a control unit that controls the vehicle on the basis ofcontents of a voice recognized from an utterance, the voice recognitiondevice comprising: a vehicle information storage unit that stores thecontents of the voice and vehicle information in association with eachother; a recognition accuracy calculation unit that calculates arecognition accuracy of the uttered voice each time the voicerecognition is performed; and an utterance estimation unit that readsthe vehicle information in a case where the recognition accuracy islower than a predetermined threshold and estimates that the contents ofthe voice associated with the vehicle information are contents of anuttered voice when the vehicle information that has been read is in thevehicle information storage unit, wherein in a case where the contentsof the voice are estimated by the utterance estimation unit, the controlunit controls the vehicle on the basis of the estimated contents of thevoice.
 7. The voice recognition device for a vehicle according to claim6, further comprising: an utterance subject identification unit thatidentifies an utterance subject of the voice, wherein the vehicleinformation storage unit stores the vehicle information for eachutterance subject in association with the contents of the voice thereof,and the utterance estimation unit retrieves the utterance subjectidentified by the utterance subject identification unit from the vehicleinformation storage unit and estimates the contents of the voicecorresponding to the utterance subject, in a case where the utteredvoice contents are estimated on the basis of the vehicle information.